This invention relates to multimedia conferencing via the public switched telephone network (hereafter, the PSTN) and data networks external to the PSTN. As used herein, "multimedia conferencing" means voice telephone conferences accompanied by presentations of displayable images, and the PSTN refers to equipment throughout the world enabling users of voice telephones (private and public ones) to connect to each other, including mobile radio systems but excluding equipment maintained or leased for exclusive use of private enterprises (PBX's, leased lines, etc.) as well as public data transmission systems capable of handling voice transmissions (e.g. the Internet and World Wide Web). More specifically, this invention concerns a system for multimedia conferencing wherein conference participants can coordinate display of images (e.g. charts) with voice presentations, and also directly control or administer functions or services of the PSTN that normally are inaccessible while a conference session is active.
Present conference management resources of the PSTN support conferencing services between voice telephone users wherein two or more users remote from one another (hereinafter, participants, conferees or attendees) can converse as if connected to a party line. In addition to overseeing connections between participants, these management resources control other conference parameters, such as the maximum number of participants to be accommodated, the maximum duration of the session, connection of new participants, notification of participants when a new participant is added, etc.
The present infrastructure of the PSTN also allows for direct transmission of data between PSTN subscribers (e.g. facsimile data, computer data, etc.), and may be used to support transmission of data between parts of global data networks like the Internet and World Wide Web (hereafter, the Web or WWW). Parts of such data networks are physically and logically external to the PSTN in that they do not form or take part in forming end-to-end connections between ordinary voice telephones in response to direct dialing (or tone keying). Parts external to the PSTN include for instance equipment maintained by Internet access providers, which is not subject to control by the PSTN, even when conducting transmissions over the data network and even if connected to the PSTN while doing so. Notably, in addition to lacking control of such external parts, the PSTN has no control over the routing of transmissions between them via transmission lines in the data network.
Furthermore, even if voice signals are transmitted through the data network, the PSTN has no control over their routing within the data network. Hence, even parts of the Internet/Web that may carry voice signals are external to the PSTN, even if the signals are generated and/or reproduced in telephones or telephone-like apparatus (e.g. microphones and speakers connected to computers and conveyed through modems), if the PSTN can not control those parts.
Similarly, private networks containing transmission lines leased from the PSTN (T1 lines, T2 lines, etc.), may include parts that are not subject to PSTN control, which therefore are external to the PSTN regardless of what signals they carry (data, voice, or other).
Consequently, users of PSTN conferencing services can not presently operate through either external networks or their telephones to administer complex services within the PSTN; particularly, while a conference is in session.
The present invention seeks to overcome conferencing limitations of both the PSTN and networks external thereto (particularly, public data networks like the Internet and Web), to enable participants in a multimedia conference to use external networks to vary services received in the PSTN during the conference; without required intervention of PSTN operators or other PSTN representatives. This is accomplished by outfitting the PSTN with conference servers that are administered and controlled by the PSTN but have links to external networks. The conference servers are so constructed and located as to enable participants in a multimedia conference to control distribution of display images to other participants through public data networks (e.g. the Internet) in coordination with their voice presentations, and to permit such control at a cost that can be attractive to both the PSTN and its customers. The conference servers are also so constructed and configured within the PSTN as to allow participants in a multimedia conference to control services internal to the PSTN (both existing services such as conference outdialing and new ones) by means of signal requests communicated through external networks.